This invention relates to a novel tube loader for use with a semiconductor testing system. More specifically, this invention relates to a tube loader which increases the speed at which semiconductor devices may be input to an inspection station, thereby making the system more efficient.
After fabrication, semiconductor chip packages such as plastic lead chip carriers (PLCC) are often inspected by testing machines to insure that each finished package conforms to performance standards. One such testing machine is a lead inspection station which determines whether the leads on individual chips are properly fabricated, and detects other defects such as lead deformities. Other tests include those which test electrical properties, determine lead pitch accuracy and inspect lead coplanarity. In this type of testing system, packages are loaded into the testing machine and an optical scanner determines whether the devices are properly fabricated. Each device is individually scanned and then a pick and place machine loads the device onto one of a multiplicity of output tracks. For example, there may be three output tracks so that the devices may be separated according to whether the device is qualified as bad, marginal, or good by the inspection station.
The packages or devices under test (DUT) are usually transported and handled in clear elongated tubes. The tubes are rectangular in cross-section, and the packages are positioned in a single row along the length of a tube. The tubes are capped at both ends during transport to prevent the devices from sliding out of the tubes. In the past, the devices have been input to the testing system by feeding them from a loading tube into the inspection station along a single input track. An operator monitors the inspection station and feeds the devices into the station via the loading track one tube at a time. The efficiency of testing systems is thus limited by the speed at which the devices are loaded onto the loading track.
The difficulties suggested in the preceding are not intended to be exhaustive but rather are among many which may tend to reduce the efficiency of prior art testing stations. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that semiconductor testing stations appearing in the past will admit to worthwhile improvement.
It is therefore a general object of the invention to enhance the effectiveness of prior art semiconductor testing systems.
It is a specific object of the invention to provide a device which increases the speed at which devices may be loaded onto a prior art semiconductor inspection station.
It is another object of the invention to provide a device which minimizes the amount of time which an operator must monitor the semiconductor inspection stations of the prior art.
It is still another object of the invention to provide a device which decreases the overall time required to test and inspect a predetermined number of devices.